1. Field of the Invention
The present invention relates to a test of a semiconductor device utilizing electron beam. Particularly, the present invention relates to a device test in which the quality of a sample to be tested is determined by measuring electric current flowing through the test sample when the latter is irradiated with electron beam.
2. Description of the Related Art
There has been a semiconductor device tester for testing contact holes or through-holes of a semiconductor device by utilizing electron beam. For example, JP H10-281746A discloses a semiconductor device tester in which a contact hole is irradiated with electron beam and the contact hole is decided as opened when a current flows through the device and decided as not opened when no current flows. In this semiconductor device tester, a diameter of a bottom of the contact hole can be measured by a time difference of current measured correspondingly to electron beam scan time.
With the popularization of SOC (System-On-Chip) semiconductor devices, logic circuits such as memories and CPU, etc., have been formed in a semiconductor device. Since, in general, there is no regularity of layout of a logic circuit, positions of contact holes are generally arranged at random. The above mentioned technique can be utilized in order to test the contact holes arranged at random.
However, in order to reflect the measured current to the quality of the contact hole, it is necessary to know a portion of the measured current corresponding to the contact hole. Therefore, it is necessary to obtain an information of positions of all of contact holes by using CAD data and to prepare the data for every semiconductor device.
On the other hand, with the recent accelerated popularization of semiconductor device integration, semiconductor devices exceeding 10 billions in number can be integrated on one chip. In such case, a memory capacity necessary to memorize a layout of each of layers of the chip becomes several G bytes. It is practically impossible to prepare a tester for one device and there are many kinds of logistic device produced in a mass production factory. Therefore, in order to specify positions of through-holes by using CAD data, it is necessary to accumulate a massive amount of data and it is difficult to accumulate all of the data in a single tester.